In many industries, there are found mechanical devices with complicated metal parts. Such industries include aerospace, transportation, nuclear, power transmission, communications, petrochemical, drilling and related industries. Exemplary of the mechanical devices mentioned is the gas turbine including a turbine case having a large number of turbine vanes which are subjected to accelerated wear and/or failure due to high stresses, elevated temperatures and environments rich in erosive and corrosive agents. The turbine vanes typically have spaced apart convex and concave surfaces joined on opposite edges by a rounded leading edge and a converging trailing edge. The vanes are joined to cylindrical or conical flowpath walls at one or both sides.
As can be appreciated, turbines are of an extremely complex design, costly to manufacture and, all things considered, have a limited operational service life. Therefore, it is desirable to repair or refurbish these components rather than replace them. Techniques for replacing part or all of the vanes in a turbine rotor are disclosed in U.S. Pat. Nos. 3,650,635; 3,802,046; 4,141,127; 4,305,697; 4,326,833; and 4,832,252.
Any technique for repair of turbine components must be reliable. One of the ongoing concerns of the aerospace industry has been the potential for catastrophic ingestion damage to downstream stages of the turbine upon failure of a component repaired with a simple butt joint.